Abstract: According a widely held view in the philosophy of mind, property dualism is a respectable theory whereas substance dualism need not be taken seriously. This paper argues that property dualism, as it is usually understood, is incoherent. The commitments that are meant to lead to property dualism actually lead to substance dualism. The argument presented here adds weight to David Chalmers’ suggestion that the serious nonphysicalist options are in fact various kinds of panpsychism and substance dualism. Along the way I offer an account of the substance/property distinction, argue against the existence of substrata as distinct from substances and properties, and describe a new position which I call ‘transcendent panpsychism’. I identify some reasons why philosophers of mind might have overlooked the incoherence of property dualism and finish with some thoughts on the significance of my conclusion for developmental psychologyAbstract: According a widely held view in the philosophy of mind, property dualism is a respectable theory whereas substance dualism need not be taken seriously. This paper argues that property dualism, as it is usually understood, is incoherent. The commitments that are meant to lead to property dualism actually lead to substance dualism.